PLUGIN PARA GNUPG QUE SOPORTA ALGORITMO IDEA
GnuPG desde la versión 1.0.5 (ver {1}) no soporta el algoritmo de encripción IDEA por ser patentado aunque es el estándar en PGP (en particular pgpi 5.0).
! INSTALACIÓN Y CONFIGURACIÓN
Para agregar soporte a GnuPG debe:
- Descargar idea.c e idea.h. Puede ser de http://www.nosneros.net/hso/code/gnupg_idea_patches/ (al final de este artículo también están).
- Compilar con:
gcc -Wall -O2 -shared -fPIC -o idea idea.c
mkdir ~/lib/
cp idea ~/lib/
- Configurar GnuPG: en el archivo ~/.gnupg/gpg.conf agregar al final la línea:
load-extension /home/miusuario/lib/idea
REFERENCIAS
- {1} http://www.spywarewarrior.com/uiuc/gpg-idea/gpg-idea.htm
- {2} http://www.nosneros.net/hso/code/gnupg_idea_patches/
Esta información se dedica a Jesucristo por su Paciencia y se libera al dominio público. vtamara@pasosdeJesus.org 2008.
! idea.h
const char *
idea_get_info( int algo, size_t *keylen,
size_t *blocksize, size_t *contextsize,
int (**r_setkey)( void *c, byte *key, unsigned keylen ),
void (**r_encrypt)( void *c, byte *outbuf, byte *inbuf ),
void (**r_decrypt)( void *c, byte *outbuf, byte *inbuf )
);
! idea.c
/* idea.c - IDEA algorithm
* Copyright (c) 1997, 1998, 1999, 2001, 2002 by Werner Koch (dd9jn)
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* WERNER KOCH BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Except as contained in this notice, the name of Werner Koch shall not be
* used in advertising or otherwise to promote the sale, use or other dealings
* in this Software without prior written authorization from Werner Koch.
*
* DUE TO PATENT CLAIMS THE DISTRIBUTION OF THE SOFTWARE IS NOT ALLOWED IN
* THESE COUNTRIES:
* AUSTRIA, FRANCE, GERMANY, ITALY, JAPAN, THE NETHERLANDS,
* SPAIN, SWEDEN, SWITZERLAND, THE UK AND THE US.
*/
/*
* Please see http://www.noepatents.org/ to learn why software patents
* are bad for society and what you can do to fight them.
*
* The code herein is based on the one from:
* Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996.
* ISBN 0-471-11709-9. .
*
* How to compile:
gcc -Wall -O2 -shared -fPIC -o idea idea.c
*
* 2001-06-08 wk Changed distribution conditions
* 2001-06-11 wk Fixed invert_key (which is not used in CFB mode)
* Thanks to Mark A. Borgerding. Added definition for
* the PowerPC.
* 2002-08-03 wk Removed dependeny to g10_log_fatal and perform selftest
* in idea_get_info.
*/
#include
#include
#include
#include
/* configuration stuff */
#ifdef __alpha__
#define !SIZEOF_UNSIGNED_LONG 8
#else
#define !SIZEOF_UNSIGNED_LONG 4
#endif
#if defined(__mc68000__) || defined (__sparc__) || defined (__PPC__) \
|| (defined(__mips__) && (defined(MIPSEB) || defined (__MIPSEB__)) ) \
|| defined(__powerpc__) \
|| defined(__hpux__) /* should be replaced by the Macro for the PA */
#define !BIG_ENDIAN_HOST 1
#else
#define !LITTLE_ENDIAN_HOST 1
#endif
typedef unsigned long ulong;
typedef unsigned short ushort;
typedef unsigned char byte;
typedef unsigned short u16;
typedef unsigned long u32;
/* end configurable stuff */
#ifndef DIM
#define DIM(v) (sizeof(v)/sizeof((v)![0]))
#define DIMof(type,member) DIM(((type *)0)->member)
#endif
/* imports */
void g10_log_fatal( const char *fmt, ... );
/* local stuff */
#define FNCCAST_SETKEY(f) ((int(*)(void*, byte*, unsigned))(f))
#define FNCCAST_CRYPT(f) ((void(*)(void*, byte*, byte*))(f))
#define IDEA_KEYSIZE 16
#define IDEA_BLOCKSIZE 8
#define IDEA_ROUNDS 8
#define IDEA_KEYLEN (6*IDEA_ROUNDS+4)
typedef struct {
u16 ek![IDEA_KEYLEN];
u16 dk![IDEA_KEYLEN];
int have_dk;
} IDEA_context;
static int do_setkey( IDEA_context *c, byte *key, unsigned keylen );
static void encrypt_block( IDEA_context *bc, byte *outbuf, byte *inbuf );
static void decrypt_block( IDEA_context *bc, byte *outbuf, byte *inbuf );
static int selftest(int);
static u16
mul_inv( u16 x )
{
u16 t0, t1;
u16 q, y;
if( x < 2 )
return x;
t1 = 0x10001L / x;
y = 0x10001L % x;
if( y ``` 1 )
return (1-t1) & 0xffff;
t0 = 1;
do {
q = x / y;
x = x % y;
t0 += q * t1;
if( x ``` 1 )
return t0;
q = y / x;
y = y % x;
t1 += q * t0;
} while( y != 1 );
return (1-t1) & 0xffff;
}
static void
expand_key( byte *userkey, u16 *ek )
{
int i,j;
for(j=0; j < 8; j++ ) {
ek![j] = (*userkey << 8) + userkey![1];
userkey += 2;
}
for(i=0; j < IDEA_KEYLEN; j++ ) {
i++;
ek![i+7] = ek![i&7] << 9 | ek![(i+1)&7] >> 7;
ek += i & 8;
i &= 7;
}
}
static void
invert_key( u16 *ek, u16 dk![IDEA_KEYLEN] )
{
int i;
u16 t1, t2, t3;
u16 temp![IDEA_KEYLEN];
u16 *p = temp + IDEA_KEYLEN;
t1 = mul_inv( *ek++ );
t2 = -*ek++;
t3 = -*ek++;
*--p = mul_inv( *ek++ );
*--p = t3;
*--p = t2;
*--p = t1;
for(i=0; i < IDEA_ROUNDS-1; i++ ) {
t1 = *ek++;
*--p = *ek++;
*--p = t1;
t1 = mul_inv( *ek++ );
t2 = -*ek++;
t3 = -*ek++;
*--p = mul_inv( *ek++ );
*--p = t2;
*--p = t3;
*--p = t1;
}
t1 = *ek++;
*--p = *ek++;
*--p = t1;
t1 = mul_inv( *ek++ );
t2 = -*ek++;
t3 = -*ek++;
*--p = mul_inv( *ek++ );
*--p = t3;
*--p = t2;
*--p = t1;
memcpy(dk, temp, sizeof(temp) );
memset(temp, 0, sizeof(temp) ); /* burn temp */
}
static void
cipher( byte *outbuf, byte *inbuf, u16 *key )
{
u16 x1, x2, x3,x4, s2, s3;
u16 *in, *out;
int r = IDEA_ROUNDS;
#define MUL(x,y) \
do {u16 _t16; u32 _t32; \
if( (_t16 = (y)) ) { \
if( (x = (x)&0xffff) ) { \
_t32 = (u32)x * _t16; \
x = _t32 & 0xffff; \
_t16 = _t32 >> 16; \
x = ((x)-_t16) + (x<_t16?1:0); \
} \
else { \
x = 1 - _t16; \
} \
} \
else { \
x = 1 - x; \
} \
} while(0)
in = (u16*)inbuf;
x1 = *in++;
x2 = *in++;
x3 = *in++;
x4 = *in;
#ifdef !LITTLE_ENDIAN_HOST
x1 = (x1>>8) | (x1<<8);
x2 = (x2>>8) | (x2<<8);
x3 = (x3>>8) | (x3<<8);
x4 = (x4>>8) | (x4<<8);
#endif
do {
MUL(x1, *key++);
x2 += *key++;
x3 += *key++;
MUL(x4, *key++ );
s3 = x3;
x3 ^= x1;
MUL(x3, *key++);
s2 = x2;
x2 ^=x4;
x2 += x3;
MUL(x2, *key++);
x3 += x2;
x1 ^= x2;
x4 ^= x3;
x2 ^= s3;
x3 ^= s2;
} while( --r );
MUL(x1, *key++);
x3 += *key++;
x2 += *key++;
MUL(x4, *key);
out = (u16*)outbuf;
#ifdef !LITTLE_ENDIAN_HOST
*out++ = (x1>>8) | (x1<<8);
*out++ = (x3>>8) | (x3<<8);
*out++ = (x2>>8) | (x2<<8);
*out = (x4>>8) | (x4<<8);
#else
*out++ = x1;
*out++ = x3;
*out++ = x2;
*out = x4;
#endif
#undef MUL
}
static int
do_setkey( IDEA_context *c, byte *key, unsigned keylen )
{
assert(keylen ``` 16);
c->have_dk = 0;
expand_key( key, c->ek );
invert_key( c->ek, c->dk );
return 0;
}
static void
encrypt_block( IDEA_context *c, byte *outbuf, byte *inbuf )
{
cipher( outbuf, inbuf, c->ek );
}
static void
decrypt_block( IDEA_context *c, byte *outbuf, byte *inbuf )
{
if( !c->have_dk ) {
c->have_dk = 1;
invert_key( c->ek, c->dk );
}
cipher( outbuf, inbuf, c->dk );
}
static int
selftest( int check_decrypt )
{
static struct {
byte key![16];
byte plain![8];
byte cipher![8];
} test_vectors[] = {
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0x00, 0x00, 0x00, 0x01, 0x00, 0x02, 0x00, 0x03 },
{ 0x11, 0xFB, 0xED, 0x2B, 0x01, 0x98, 0x6D, 0xE5 } },
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
{ 0x54, 0x0E, 0x5F, 0xEA, 0x18, 0xC2, 0xF8, 0xB1 } },
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0x00, 0x19, 0x32, 0x4B, 0x64, 0x7D, 0x96, 0xAF },
{ 0x9F, 0x0A, 0x0A, 0xB6, 0xE1, 0x0C, 0xED, 0x78 } },
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0xF5, 0x20, 0x2D, 0x5B, 0x9C, 0x67, 0x1B, 0x08 },
{ 0xCF, 0x18, 0xFD, 0x73, 0x55, 0xE2, 0xC5, 0xC5 } },
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0xFA, 0xE6, 0xD2, 0xBE, 0xAA, 0x96, 0x82, 0x6E },
{ 0x85, 0xDF, 0x52, 0x00, 0x56, 0x08, 0x19, 0x3D } },
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0x0A, 0x14, 0x1E, 0x28, 0x32, 0x3C, 0x46, 0x50 },
{ 0x2F, 0x7D, 0xE7, 0x50, 0x21, 0x2F, 0xB7, 0x34 } },
{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
{ 0x05, 0x0A, 0x0F, 0x14, 0x19, 0x1E, 0x23, 0x28 },
{ 0x7B, 0x73, 0x14, 0x92, 0x5D, 0xE5, 0x9C, 0x09 } },
{ { 0x00, 0x05, 0x00, 0x0A, 0x00, 0x0F, 0x00, 0x14,
0x00, 0x19, 0x00, 0x1E, 0x00, 0x23, 0x00, 0x28 },
{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
{ 0x3E, 0xC0, 0x47, 0x80, 0xBE, 0xFF, 0x6E, 0x20 } },
{ { 0x3A, 0x98, 0x4E, 0x20, 0x00, 0x19, 0x5D, 0xB3,
0x2E, 0xE5, 0x01, 0xC8, 0xC4, 0x7C, 0xEA, 0x60 },
{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
{ 0x97, 0xBC, 0xD8, 0x20, 0x07, 0x80, 0xDA, 0x86 } },
{ { 0x00, 0x64, 0x00, 0xC8, 0x01, 0x2C, 0x01, 0x90,
0x01, 0xF4, 0x02, 0x58, 0x02, 0xBC, 0x03, 0x20 },
{ 0x05, 0x32, 0x0A, 0x64, 0x14, 0xC8, 0x19, 0xFA },
{ 0x65, 0xBE, 0x87, 0xE7, 0xA2, 0x53, 0x8A, 0xED } },
{ { 0x9D, 0x40, 0x75, 0xC1, 0x03, 0xBC, 0x32, 0x2A,
0xFB, 0x03, 0xE7, 0xBE, 0x6A, 0xB3, 0x00, 0x06 },
{ 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08 },
{ 0xF5, 0xDB, 0x1A, 0xC4, 0x5E, 0x5E, 0xF9, 0xF9 } }
};
IDEA_context c;
byte buffer![8];
int i;
for(i=0; i < DIM(test_vectors); i++ ) {
do_setkey( &c, test_vectors![i].key, 16 );
if( !check_decrypt ) {
encrypt_block( &c, buffer, test_vectors![i].plain );
if( memcmp( buffer, test_vectors![i].cipher, 8 ) )
{
fprintf (stderr, "idea encryption (%d) failed\n", i);
return -1;
}
}
else {
decrypt_block( &c, buffer, test_vectors![i].cipher );
if( memcmp( buffer, test_vectors![i].plain, 8 ) )
{
fprintf (stderr, "idea decryption (%d) failed\n", i);
return -1;
}
}
}
return 0;
}
/*
* Return some information about the algorithm. We need algo here to
* distinguish different flavors of the algorithm.
* Returns: A pointer to string describing the algorithm or NULL if
* the ALGO is invalid.
*/
const char *
idea_get_info( int algo, size_t *keylen,
size_t *blocksize, size_t *contextsize,
int (**r_setkey)( void *c, byte *key, unsigned keylen ),
void (**r_encrypt)( void *c, byte *outbuf, byte *inbuf ),
void (**r_decrypt)( void *c, byte *outbuf, byte *inbuf )
)
{
static int initialized = 0;
if( !initialized ) {
initialized = 1;
if ( selftest(0) || selftest(1) )
return NULL;
}
*keylen = 128;
*blocksize = 8;
*contextsize = sizeof(IDEA_context);
*r_setkey = FNCCAST_SETKEY(do_setkey);
*r_encrypt= FNCCAST_CRYPT(encrypt_block);
*r_decrypt= FNCCAST_CRYPT(decrypt_block);
if( algo ``` 1 )
return "IDEA";
return NULL;
}
const char * const gnupgext_version = "IDEA ($Revision: 1.11 $)";
static struct {
int class;
int version;
int value;
void (*func)(void);
} func_table[] = {
{ 20, 1, 0, (void(*)(void))idea_get_info },
{ 21, 1, 1 },
};
/*
* Enumerate the names of the functions together with informations about
* this function. Set sequence to an integer with a initial value of 0 and
* do not change it.
* If what is 0 all kind of functions are returned.
* Return values: class := class of function:
* 10 = message digest algorithm info function
* 11 = integer with available md algorithms
* 20 = cipher algorithm info function
* 21 = integer with available cipher algorithms
* 30 = public key algorithm info function
* 31 = integer with available pubkey algorithms
* version = interface version of the function/pointer
* (currently this is 1 for all functions)
*/
void *
gnupgext_enum_func( int what, int *sequence, int *class, int *vers )
{
void *ret;
int i = *sequence;
do {
if( i >= DIM(func_table) || i < 0 ) {
return NULL;
}
*class = func_table![i].class;
*vers = func_table![i].version;
switch( *class ) {
case 11:
case 21:
case 31:
ret = &func_table![i].value;
break;
default:
ret = (void*)func_table![i].func;
break;
}
i++;
} while( what && what != *class );
*sequence = i;
return ret;
}
</pre>